Impact pulverizer



March 29, 1927.

v v B62269? A. B. WILLOUGHBY IMPACT PULVERIZER Filad Jan, 31, 1925 sSheets-Shut 1 INVENTOE w, MESS W firmmvgy March 1927' A. B. WILLOUGHBYIMPACT PULVERIZER Filed Jan. 51, 1925 3 Shoots-Sheet 2 INVENTOI? w/T'NESS HTTORNE) A. B. WILLOUGHBY IMPACT PULVERIZER Filed Jan. 3l, 1925 3Shoots-Shoot 5 w/ TNESS Patented Mar. 29, 1927.

ALFRED it. w-rnnouennr; or PHILADELPHIA, PENNSYLVANIA.

IMPACT PUIi-VERIZER'J Application filed January 4 My invention relatesto impact pulverizers of the type or class in which two alined andopposing streams of material to be, pulverized are discharged at a highvelocity against 5 each other by jets of superheatedsteam to reduce thematerial in saidstreams to a fine powdered condition by the impact ofthe pieces against each other.

The type of apparatus to which my invention relates is exemplifiediii-U. Letters Patent No. 1,246,514, granted to me November 13, 1917 andthe present inventioninvolves certain improvements in suclrapparatus.

The object of the present invention is to increase the capacity or rateat' which material reduced to a powdered condition may be removed fromthe chamber in'wh-ichitis reduced to its powdered condition; IQ removethe material substantially as fast as it is formed in the pulverizing orimpactchamher, and to so construct said chamber that the finely powderedmaterial may not collect andv accumulate int-he said chamber or becomemixed and carried along with the larger particles which,..in the normaloperation of the device, are resubjectedto the action-t the pulverizer.

Further object-s ot my invention; are to provide an impact orpulverizin-g chamber in whichall the material, after impaot,-is forcedto pass transversely through-a fluid current to completely separatethepulverized material from the particles which are. not pulverized andwhich require a retreatment; to provide a structure whereby all of thefragments which require further treatment are immediately discharged orconducted out of the pulverizing chamberand mayznot-accumulate therein.

A further. objectv of my. invention is to cause the heavier particles totravel over and to keep clear of powdered material, any surface insideof said casing. upon which said powdered material might tend toaccumulate.

A further object of my invention is to cause all the unpu-lverizedmaterialafte r impact to move toward and discharge through an opening inthe bottom of the pnlverizer chamberthrough which air is beingdrawn intothe pulverizingchamber.

A further object of my invention is, to provide the pulverizing. boxorchamber with a. large number oi'exhaust pipes or conduits, eachprovided with an ejector so that when 31, 1925. S eri.a1 No-. 5,827.

material is, being rapidly pulverized it may be removed 'from thepulverizing chamber as fast as is formed without increasing the rate atwhich any one ejector may be operating. It may here be explained'thatejectors, employed in pulverizing apparatus of the type referred toherein are more or less uncertainin their operation when it is attemptedtowoperate them under varying con ditions; that is to say, when thesteam at just the right velocit-yand quantity is forced into: andthrough the Venturi tube, the ejector operates-very satisfactorily. Theamount and speedof the projecting fluid which will operate. mostefli'ciently. with a particular Venturi tube are determined more or lessby experimentation, and after a particular ejector has been so adjustedto operate properly the ejector is eificient. But any attempt to makethe action of an ejector of'this type more rapid, as by increasing theamount of steam delivered thereto, may result in a substantial'decreasein the efliciency of the apparatus; It is, therefore, highlydesirable to operate the 'ejectors under constant conditions that is tosay, with that pressure and a volume of steam which'operates mostetficiently withthe-Venturi tube of the particular ejector.

The. speed atwhich 7 different materials may be pulverized in an impactpulverizer depends, of course, upon materials. materials are reduced toa powder much more quickly than others; .Therefore, the Speed at whichthe material may be taken from the pulverizer chamber varies withdifferent materials. lVith amaterial which is easily reduced,i,thepowdered materialmay be formed in the pulverizingch'amber faster than itcan be carried away by a single ejector, and to remove the material asfast as it is formed, being one of the objects of the present invention,.1 accomplish the removal by providing the side and'top walls of thep'ulverizing chamber each with an independentejector apparatus so that,for instance, in treating a readily pulverized material, two or three oreven four independent ejectors maybe simultaneously operated, eachoperating under the conditions best suited or peculiar to itself. Whenone, two or more ejectors are operating simultaneously, each ejectorwillact as itwould if it were operating alone, In treating materialswhich are reduced with-difficulty, and therefore re].-

Some

atively suffice to remove the pulverized material as fast as it isformed.

Other objects of my invention will. appear in the specification and.claims below.

In the drawings forming a part of this specification and in which thesame reference characters are used throughout the various views todesignate the same parts,

Fig. 1 is a front elevational view, partly in section of a pulverizcrembodying my invention.

Fig. 2 is a side elevatioual view of the same, partly in section.

Fig. is a plan view of the same, parts being broken away to show theinterior of the pulverizcr chamber; and

Fig. 4 is a more or less diagrammatic view of an arrangement wherebyvarying amounts of pulverized material may be removed from thepulverizing chamber.

The apparatus comprises a pair of hoppers 1-1, the lower ends of whichare arranged to discharge into chambers 22 provided in the casing 3,said chambers each surrounding a steam nozzle 4: rigidly secured byscrewthreads 5 to the rear wall of the chamber 2. The passage 6 throughthe steam nozzle t is in alinement with an opening 7 through the,casing, communicating with the end of a steam pipe 8 through which steamsuperheated to high temperatures and at a high pressure, is conducted tothe nozzles. Into the outer end of each nozzle t is secured a tube ornipple 9 of very hard steel, the nipple being preferably secured to thenozzle by screwthreads 10. The jet openings 11 through the nipples 9 areof very small diameter and the superheated steam from the pipe 8 willissue therefrom at very high pressure and velocity. The side of eachchamber 2 opposite that to which the steam pipes 8 are attached ispreferably provided with a large openi 12 into which is rigidly securedin any suitable manner a bushing 13 having aconcentric circular hole 1sttherethrougli into which are tightly fitted wearing tubes 15 of hardsteel, each having an axial tapering passage 1( therethrough in axialalinement with the axis of the passage 11 through the steam nipples 9.

The adjacent ends of the wearing tube 15 are provided with a. flange 17fitting against and substantially covering the inner faces of thebushings 13. The wearing tubes are preferably secured to the bushings byset screws 18 so that when the wearing tubes become worn they may bereadily replaced.

The inner ends of the bushings l3 and wearing tubes 15 are enclosedwithin a suit able casing or housing 19 forn'iing the im pact orpulverizing chamber 20. The side walls 21, 22 of the pulverizing chamberare preferably vertical and are parallel but they slowly, one ejectorapparatus might are preferably spaced further apart from each otheratthe rear of the apparatus (see Fig. 3) thai'i at the front to providean enlarged portion in which the separatioi'i of the powder from theunpowdercd material may be more readily effected.

The top wall of the pulverizcr chamljicr it comprises two portions,namely, the horizontal wall portion 23 forming the top of the separatingportion 20 of the chan'iber,

and the inclined portion 2% extending forv wardly and downwardly fromthe front edge of the wall .23 to a. position in front of and Rtll)i;ltllltlzlll 'y at the level of the axis of the nozzles 4-. The rearwall 25 of the pulvcrizing chamber is prefcral'ily vertical.

he bottom wall of the pulverizcr chamber 20 preferably comprises twodownwardly converging steeply inclined walls 26 and 27, the lower endsof which are spaced from each other to provide a relatively narrow andlong passage 28 extending the full width of said chamber.

The pulverizcr chamber is preferably constructed in two parts, an upperpart or portion and a lower part or portion respectively provided withflanges 29 and 30 secured together with bolts 31.

The top horizontal wall 28, the rear vertical rail 25 and the upperportion of the side walls 21 and 22 are each provided re spectively witha large opening 32, ach communicating with a relatively large conveyorpipe or tube 33 having a Venturi tube 34 therein.

The Venturi tubes 34; are preferably rc movable so that they may bereadily replaced when worn, and cooperating with each Venturi tube is anozzle 35 at the end of a steam pipe 36 arranged axially of the tube 3stin which it may be and arranged to discharge a jet of steam at hightemperature and pressure into and through said Venturi tube to produce acurrent of air and steam through the tube 33 to draw the powderedmaterial out of the pulverizcr chan'ibcr and to convey it to a suitablesettling chamber (not shown).

Each pipe 36 is preferably located axially of the conveyor tube 33 inwhich it is anil serves the double purpose of conveying steam to the lenturi tubes and of reheating the conveyor fluid to prevent the'ffilli'llllfill of moisture therein between the pulverizcr chamber andthe ejector. The steam must be kept dry in order to convey the powderfloating therein and to deliver it into the settling chan'ibcrs in a drycondition.

Near the point where the conveyor tubes 38 join to the pulverizcrchamber, each steam pipe is connected to a branch pipe 3. extendingradially through the tube 33 and provided with a hand controlled valve38. These pipes 37 communicate with a suitable source of steam supplyand the valves 38 make it possible for the operator to use as manyconveyor tubes as may be requiredto carry off the material as fastas itis formed in the pulverizing chamber and to properly adjust the amountof steam delivered to the Vent-uri tube by. each conveyor so that eachVenturi tube may be supplied with List the right amount of steam to.operate efliciently independently of any other. conveyor tube.

Below the chamber 2 inthe casing 3 and forming the lower wall of saidchamber 2 is a closure or gate 39 preferably pivoted on a bolt 40 sothat the closure 39 maybe swung to one side when the handle 41 thereofis grasped and turned about the pivot to give access to the chamber 2"whenever necessary.

Above the hopper 1, 1 is a main-hopper 1-2 having its lower endbifurcated to form chutes 13, 43, terminating respectively over thehoppers 1, 1.. The lower end of' each chute 13 is preferably providedwith a gate 14 pivoted on a stud 45 provided with a handle 46 so thatthe discharge of material from the main hopper 4:2 to either hopper 1may be interrupted when desired.

Beneath the opening 28 at the bottom of the pulverizer chamber 20 is achute or hopper 47 into which the particles of material being treatedand which have not been reduced to a powder will fall by gravity. In theoperationof this type of pulverizer, the chute 17 delivers materialpassing therethrough-to a suitable conveyor mechanism by meansof whichthe material which has not been reduced to the requisite fineness iscarried back to the top .of the apparatus and discharged'again intothehopper for retreatment.

I preferably provide the chute 4:7 with branches 48 and 19 extendingupwardly and having their upper ends respectively under the gates-orclosures 39 so that when either of saidclosures are opened for anyreason, any material which may be in the chamber 2 may fall directlyinto a branch chute 18 or 49 and be carried bythe main chute to theconveyor system.

The operation of my device is as follows: Material tobe pulverized'isintroduced in the pulverizer from the hopper 42 through the branchchutes 43 into the hoppers 41 of the machine and the material to betreated substantially. fills the hoppers 1 and the chambers 2surroundingthe steam nozzle 4. Supcrheated steam at high temperature andpressure is admitted through the steam pipes 8 to the steam nozzles 4and the jets of steam drive through the tapered passage 16 in thewearing tubes impelling forward with it at high speed thematerial to bepulverized which may bein the chambers 2, 2 and tapered passages 16, 16.Two streams of solid material thus are impelled at high velocity againsteach other, it-' being new plain that the axes of the passages 6 throughthe nozzles lm-ust be in alinement and the taperedpassages 16 being alsoinalinement with each other.. The force of the impact of the particlesor pieces of. solid matter against each ot ierpulve'rizes them and thedust and powder together with the particles which havenot beenreduced'to powdered form, fly in all directions radially from the pointof impact'whichis substantially midway between the nozzles 4L.

The powdered material is suspendedin and floats in the air and steam asan impalpable powder and the whole .pulverizing chamber 20 isimmediatelyfllled with this powder. The conveyor system havingbeen started "at thesame time by. opening one or more of the valves 38, the st'oam'from theend of the nozzle of'the conveyor driving through the Venturi tube 3%,creates a draft or. suction" in the conveyor pipes 33 and draws thefluid (steam and air) up into the conveyor tubeor tubes from thepulverizing chamber 20 and draws it through the Venturi tube and on tosuitable settling chambers.

It .is to be notedthat the inside of the pulverizer chambers. containsno levelor approximately level "shoulders or surfaces. The rear wall 25is, vertical. The front wall 24is inclined downwardly. The bottom walls26 and 27 slant downwardly sharply and no material of'substantial weightcan settle and remain thereon; However, the fragments or particles ofsolid materialwhich have not been reduced to powdered form are violentlythrown and scattered overthe entire interior surface of the. pulverizingchamber 20 and being too heavy to be carried by the draft ofairprovidedin the/conveyor 33 fall onto the sharply inclined walls 26and 27 and slide. down over the inner surfaces of the walls disl'odg'ingany powder that might stick thereto and out through the opening 28 intothe chute4. Butthe movementof the heavier particles in the impact or.pulverizing chamber is, generally speaking, transverseto and eventuallyagainstthe direction of the current of air 01 steam'in the pulverizingchamber and drawn into the conveyor tubes; that is to say, thedirectionof the gaseous fluid in the pulverizing chamber is from thenozzles upwardly toward the conveyor tubes and from the opening orpassage 28 up'wardly"to the conveyor tubes, while the direction of agreat many of the heavier particles is either across. the pul verizerchamber against the vertical rear wall 25 or downwardly against theinwardly inclined walls 26 and 27 and eventually all the heavierparticles will'fall down through the opening or passage'28.- Inv sofalling their movement is againstthe movemen'tzof the gaseous fluid inthe pulverizing cham her. This movement of the heavier particlestransverse to or against the direction of the fluid current frees themof the fine particles which are readily taken away through the conveyortubes, and as these heavier particles strike against the inner walls ofthe conveyor chamber or slide down over the inclined walls 26 and 27they loosen and free any light particles which might adhere to the wallsand, being loosened, these light particles are carried upwardly by thecurrent of steam and air and out of the chamber by the conveyor tubes.

If the nature of the material being treated is such that it is rapidlyreduced to a powdered condition, and, for instance, two conveyors whichmay be operating are not removing the powdered material from the chamber20 as fast as it is formed, or as fast as it may be desired to removeit, one or more other conveyors may be put into operation to remove thepulverized material without disturbing the adjustment or operation orinterfering with the etiicient operation of the two conveyors which werealready operating.

lVhen, on the other hand, the nature of the material is such that it isslowly reduced to a powdered condition, the quantity of pulverizcdmaterial produced may be so small that itmay be removed from thepulverizing chamber by operating a single conveyor.

From the above it will be seen that by reason of the construction of thepulverizing or impact chamber and the action and movements of theincompletely treated and insufficiently reduced particles and thedirection of the fluid current through the chamber all cooperatingtogether, the interior of the pulverizing or impact chamber is keptclean of any accumulation of completely reduced powdered material. Thereare no surfaces in the chamber on which the powder may lodge and remainand the powdered material is kept suspended in the fluid traveling outof the pulverizing chamber and is carried along with the fluid throughthe tubular conveyors to suitable settling chambers.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. In an impact pulverizer in which two alined and opposed streams ofmaterial to be pulverized are discharged against each other impelled byjets of superheated steam under high. temperature, pressure and velocitywhereby the impact of the pieces against each other reduce them to apowder, the combination of a casing, forming an impact chamber andenclosing said jets and having an opening through the bottom thereof,below and offset horizontally from the vertical passing through the axesof said jets, a bottom wall of said casing being inclined sharplydownwardly under both of said jets, disposed in a plane parallel to theaxes of said jets and tern'iinating in said opening whereby unpulverizedmaterial striking against said inclined wall slides downwardly on saidwall to said opening, and an ejector communicating with the interior oi?said casing to remove the powdered material floating therein and toseparate said powdered material from the heavier particles.

2. In an impact pulverizer in which two alined and opposed streams ofmaterial to be pulverized are discharged against each other impelled byjets of superheated steam under high tem 'ierature, pressure andvelocity whereby the impact 01 the pieces against each other reduce themto a powder, the combination of a casing, forming an impact chamber andenclosingsaid jets and having an opening through the bottom thereototl'- set horizontally from the vertical passing through the axes ofsaid jets, a bottom wall of said casing being inclined sharplydownwardly under both of said ets and terminating in said openingwhereby unpulverized material striking against said inclined wall slidesdownwardly on said wall to said opening, and an ejector communicatingwith the interior of said casing to remove the powdered materialfloating therein and to separate said powdered material from the heavierparticles, said heavier particles falling by gravity out of said casingthrough said opening.

3. The combination with an impact pulverizer comprising a pair of alinednozzles spaced apart and arranged to discharge toward each other streamsof small pieces of solid matter impelled by superheated steam at hightemperature, pressure and velocity whereby said pieces are pulverized bytheir impact against each other, of a casing forming an impact chamberand enclosing said nozzles, a bottom wall of said casing being inclinedsharply downwardly, extending un der both of said nozzles andterminating in an opening below said jets and substantially offset fromthe vertical passing through the axes of said jets whereby any materialfrom said nozzles not reduced to powder and striking said bottomwallwill slide downwardly over the surface of said wall to said opening andan exhaust tube communicating with the interior oi. said casing at theupper portion thereof, and means to create a current of gaseousconveying fluid from said impact chamber through said exhaust tube toremove the pulverized material floating in said chamher and to separatesaid pulverized material from the heavier particles.

l. The combination with an impact pulverizer comprising a pair of alinednozzles spaced apart and arranged to discharge toward each other streamsof small pieces of solid matter impelled by superheated steam at hightemperature, pressure and velocity whereby said pieces are pulverized bytheir impact against each other, of a casing forniing an impact chamberand enclosing said nozzles, a bottom wall of said casing being inclinedsharply downwardly and extending directly under both of said nozzles andterminating in an opening offset laterally from the vertical passingthrough the axes of said jets whereby any material from said nozzles notreduced to powder and striking said bottom wall will slide downwardlyover the surface of said wall to said opening and an exhaust tubecommunicating with the interior of said casing at the upper portionthereof, and means to create a current of gaseous conveying fluid fromsaid impact chamber through said exhaust tube to remove the pulverizedmaterial floating in said chamber and to separate said pulverizedmaterial from the heavier particles, said heavier particles falling bygravity out of said casing through said opening.

5. The combination with an impact pulverizer comprising a pair of alinednozzles spaced apart and arranged to discharge toward each other streamsof small pieces of solid matter impelled by superheated steam at hightemperature, pressure and velocity whereby said pieces are pulverized bytheir impact against each other, of a casing forming an impact chamberand enclosing said nozzles, a. bottom wall of said casing being inclinedsharply downwardly and extending directly under both of said nozzles andterminating in an opening oiiset from the vertical passing through theaxes of said nozzles whereby any material from said nozzles not reducedto powder and striking said bottom wall will slide downwardly over thesurface of said wall to said opening and an exhaust tube communicatingwith the interior of said casing at the upper portion thereof, and meansto create and to vary the velocity of a conveying gaseous fluid throughsaid casing, comprising a plurality of Venturi tube fluid conveyorscommunicating with said cas ing and means to operate any and all of themseparately or simultaneously.

6. The combination with an impact pulverizer comprising a pair of alinednozzles spaced apart and arranged to discharge toward each other streamsof small pieces of solid matter impelled by superheated steam at hightemperature, pressure and velocity whereby said pieces are pulverized bytheir impact against each other, of a casing forming an impact chamberand enclosing said nozzles, a bottom wall of said casing being inclinedsharply downwardly and positioned directly under both of said nozzlesand terminating in an opening on one side of the vertical passingthrough the axes of said nozzles extending the full width of said casingwhereby any material from said nozzles, not reduced to powder, andstriking said bottom wall will slide downwardly on said wall out of saidopening and will prevent any accumulation of powdered material on saidwall, and means communicating with the upper portion of said casing tocreate a current of dry gas through said casing upwardly out of saidcasing to remove from said casing the powdered material floating in saidgas.

In witness whereof, I have hereunto set my hand this 30th day ofJanuary, 1925.

ALFRED B. VVILLOUGHBY.

